Polyimides are unique polymers having desirable physical and chemical properties, which include high heat resistance and exceptional strength. Polyimides can be used as wire coatings, and are suited for molding and extrusion applications.
Examples of polyimides are the condensation products of m-phenylenediamine and 2,2-bis]4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.
A variety of polyimides are described in publications such as U.S. Pat. Nos. 3,658,938; 3,850,885; 3,983,093; 3,989,670; 3,991,004; 4,073,773; 4,281,100; 4,330,666; 4,429,102; 4,433,592; 4,433,591; 4,455,410; 4,523,006; 4,550,156; 4,565,858; 4,585,852; 4,599,396; and 4,612,361.
There is a need for polymers which have the advantages of polyimides but also have improved thermal stability and solvent resistance, and improved melt-flow characteristics and rheological behavior suitable for injection molding applications.
Accordingly, it is an object of this invention to provide thermoplastic polyimides with improved properties, and provide novel aromatic diamine monomers for the production of the polyimides.
It is another object of this invention to provide polyimides characterized by an improved combination of thermal stability, solvent resistance and melt-flow properties.
Other objects and advantages of the present invention shall become apparent from the following description and examples.